Role of hypertension in progression of chronic kidney disease in children

Advocating for the inclusion of kidney health outcomes in neonatal research: best practice recommendations by the Neonatal Kidney Collaborative

Acute kidney injury (AKI) occurs in nearly 30% of sick neonates. Chronic kidney disease (CKD) can be detected in certain populations of sick neonates as early as 2 years. AKI is often part of a multisystem syndrome that negatively impacts developing organs resulting in short- and long-term pulmonary, neurodevelopmental, and cardiovascular morbidities. It is critical to incorporate kidney-related data into neonatal clinical trials in a uniform manner to better understand how neonatal AKI or CKD could affect an outcome of interest. Here, we provide expert opinion recommendations and rationales to support the inclusion of short- and long-term neonatal kidney outcomes using a tiered approach based on study design: (1) observational studies (prospective or retrospective) limited to data available within a center's standard practice, (2) observational studies involving prospective data collection where prespecified kidney outcomes are included in the design, (3) interventional studies with non-nephrotoxic agents, and (4) interventional studies with known nephrotoxic agents. We also provide recommendations for biospecimen collection to facilitate ancillary kidney specific research initiatives. This approach balances the costs of AKI and CKD ascertainment with knowledge gained. We advocate that kidney outcomes be included routinely in neonatal clinical study design. Consistent incorporation of kidney outcomes across studies will increase our knowledge of neonatal morbidity.

Resveratrol Propionate Ester Supplement Exerts Antihypertensive Effect in Juvenile Rats Exposed to an Adenine Diet via Gut Microbiota Modulation

Resveratrol, acting as a prebiotic, and propionate, functioning as a postbiotic, hold promise for preventing hypertension in chronic kidney disease (CKD). Previously, we employed propionate to enhance the bioavailability of resveratrol through esterification, resulting in the production of a resveratrol propionate ester (RPE) mixture. In this study, we purified 3-O-propanoylresveratrol (RPE2) and 3,4'-di-O-propanoylresveratrol (RPE4) and investigated their protective effects in a juvenile rat adenine-induced CKD model. To this end, male Sprague Dawley rats aged three weeks (n = 40) were divided into five groups: control; CKD (rats fed adenine); CKRSV (CKD rats treated with 50 mg/L resveratrol); CDRPE2 (CKD rats treated with 25 mg/L RPE2); and CKRPE4 (CKD rats treated with 25 mg/L RPE 4). RPE2 and PRE4 similarly exhibited blood pressure-lowering effects comparable to those of resveratrol, along with increased nitric oxide (NO) availability. Furthermore, RPE2 and RPE4 positively influenced plasma short-chain fatty acid (SCFA) levels and induced distinct alterations in the gut microbial composition of adenine-fed juvenile rats. The supplementation of RPE2 and RPE4, by restoring NO, elevating SCFAs, and modulating the gut microbiota, holds potential for ameliorating CKD-induced hypertension.

Population pharmacokinetics of lisinopril in hypertensive children and adolescents with normal to mildly reduced kidney function

AIMS

Lisinopril, an angiotensin-converting enzyme inhibitor, is a frequently prescribed antihypertensive drug in the paediatric population, while being used off-label under the age of 6 years in the USA and for all paediatric patients globally. The SAFEPEDRUG project (IWT-130033) investigated lisinopril pharmacokinetics in hypertensive paediatric patients corresponding with the day-to-day clinical population.

METHODS

The dose-escalation pilot study included 13 children with primary and secondary hypertension who received oral lisinopril once daily in the morning; doses ranged from 0.05 to 0.2 mg kg-1 . Patients were aged between 1.9 and 17.9 years (median 13.5 years) and weight ranged between 9.62 and 97.2 kg (median 53.2 kg). All data were analysed using Monolix version 2020R1 (Lixoft, France) and R version 3.6.2.

RESULTS

A 1-compartment model with first-order absorption and first-order elimination optimally describes the data. Parameter estimates of absorption rate constant (0.075 h-1 [0.062, 0.088], typical value [95% confidence interval]), volume of distribution (31.38 L 70 kg-1 [10.5, 52.3]) and elimination clearance (24.2 L h-1 70 kg-1 [19.5, 28.9]) show good predictive ability. Significant covariate effects include total body weight on elimination clearance, and distribution volume and estimated glomerular filtration rate (eGFR) on elimination clearance. The effects of eGFR on the elimination clearance are optimally described by a linear effect centred around 105 mL min-1  1.73 m-2 . The effects of body weight were implemented using fixed allometric exponents centred around an adult weight of 70 kg.

CONCLUSION

Lisinopril dose and regimen adjustments for paediatric patients should include eGFR on top of weight adjustments. An expanded model characterizing the pharmacodynamic effect is required to identify the optimal dose and dosing regimen.

Plasma and Urinary Platelet Factor 4 as Biomarkers for Cardiovascular Risk in Children with Chronic Kidney Disease

Children suffering from chronic kidney disease (CKD) have a high risk of cardiovascular disease (CVD). The early detection and diagnosis of subclinical CVD in pediatric CKD can reduce mortality later in life. Plasma factor 4 (PF4) is a chemokine released by activated platelets. We examined whether or not PF4 in the plasma and urine, its kidney function normalized ratio, and fractional excretion have differential associations with CVD risk markers in 139 youths aged 3 to 18 years old with CKD stages G1-G4. Significant negative correlations were observed between plasma PF4 and cardiovascular surrogate markers, such as the left ventricular mass index (LVMI), carotid intima-media thickness (cIMT), and pulse wave velocity (PWV). The plasma PF4/creatinine (Cr) ratio was lower in CKD children with a high daytime BP and 24 h BP, high BP load, and nocturnal non-dipping status. After adjusting for confounders, the plasma PF4 and plasma PF4/Cr ratio still independently predicted an abnormal ABPM profile. In addition, both the plasma PF4 and plasma PF4/Cr ratio presented a negative correlation with the L-arginine and asymmetric dimethylarginine ratio. These findings provide convincing evidence supporting the link between PF4 and CVD markers in pediatric CKD. Our study highlights the importance of further research to assess the performance of PF4-related biomarkers in predicting CVD events and CKD progression in children with CKD.

Pregnancy Zone Protein as an Emerging Biomarker for Cardiovascular Risk in Pediatric Chronic Kidney Disease

Cardiovascular disease (CVD) is a significant cause of mortality and morbidity among children with chronic kidney disease (CKD). The causes of pediatric CKD differ from those in adults, as congenital anomalies in the kidney and urinary tract (CAKUT) are the leading causes in childhood. Identifying ideal markers of CVD risk early is crucial for CKD children to improve their care. Previously, we screened differentially expressed proteins in CKD children with or without blood pressure (BP) abnormalities and identified pregnancy zone protein (PZP). In 106 children and adolescents with CKD stages G1-G4, we analyzed plasma PZP concentration. The associations between PZP and ambulatory BP monitoring (ABPM) profile, parameters of cardiac and carotid ultrasounds, indices of arterial stiffness, and nitric oxide (NO) parameters were determined. We observed that PZP positively correlated with arterial stiffness indices, beta index, and pulse wave velocity in CAKUT. CKD children with abnormalities in ABPM and night dipping displayed a higher PZP concentration than those without. Additionally, the PZP level was positively correlated with NO bioavailability. In conclusion, our results suggest PZP has differential influences on cardiovascular risk in CAKUT and non-CAKUT children. Identification of this relationship is novel in the pediatric CKD literature.

Cardiovascular Risks of Hypertension: Lessons from Children with Chronic Kidney Disease

Hypertension is the most common complication of chronic kidney disease (CKD) in children, having a strong association with subsequential cardiovascular disease (CVD). In pediatric CKD, a considerable percentage of children with hypertension are undiagnosed or undertreated. Prior research has evaluated structural and functional markers of subclinical CVD and biomarkers in adults with CKD, while ideal biomarkers in pediatrics are still insufficiently studied. The ultimate goal of this review is to summarize what is currently known about state of hypertension, cardiovascular risk factors, and potential CVD markers/biomarkers in children with pre-dialysis CKD. We discuss omics-related biomarkers and the pathophysiologic processes of endothelial dysfunction, kidney injury, oxidative stress and inflammation that are classified by specific biomarkers. Moreover, we illustrate the existing challenges and highlight the paucity of pediatric CKD research to evaluate these CVD biomarkers for future clinical pediatric practice. Thus, achieving clinical utility of CVD biomarkers for use in pediatric CKD remains a significant challenge requiring additional efforts.

Agreement between attended home and ambulatory blood pressure measurements in adolescents with chronic kidney disease

BACKGROUND

This study aimed to compare attended home blood pressure (BP) measurements (HBPM) with ambulatory BP monitor (ABPM) readings and examine if level of agreement between measurement modalities differs overall and by subgroup.

METHODS

This was a secondary analysis of data from a 2-year, multicenter observational study of children 11-19 years (mean 15, SD = 2.7) with chronic kidney disease. Participants had 3 standardized resting oscillometric home BPs taken by staff followed by 24-h ABPM within 2 weeks of home BP. BP indices (measured BP/95%ile BP) were calculated for mean triplicate attended HBPM and mean ABPM measurements. Paired HBPM and ABPM measurements taken during any of 5 study visits were compared using linear regression with robust standard errors. Generalized estimating equation-based logistic regression determined sensitivity, specificity, negative, and positive predictive values with ABPM as the gold standard. Analyses were conducted for the group overall and by subgroup.

RESULTS

A total of 103 participants contributed 251 paired measurements. Indexed systolic BP did not differ between HBPM and daytime APBM (mean difference - 0.002; 95% CI: - 0.006, 0.003); the difference in indexed diastolic BP was minimal (mean difference - 0.033; 95% CI: - 0.040, - 0.025). Overall agreement between HBPM and 24-h ABPM in identifying abnormal BP was high (81.8%). HBPM had higher sensitivity (87.5%) than specificity (77.4%) and greater negative (89.8%) than positive (73.3%) predictive value, and findings were consistent in subgroups.

CONCLUSIONS

Attended HBPM may be reasonable for monitoring BP when ABPM is unavailable. The greater accessibility and feasibility of attended HBPM may potentially help improve BP control among at-risk youth. A higher resolution version of the Graphical abstract is available as Supplementary information.

Patient and caregiver perspectives on blood pressure in children with chronic kidney disease

BACKGROUND

Over 50% of children with chronic kidney disease (CKD) have uncontrolled hypertension, increasing their long-term risk of cardiovascular disease and progression to kidney failure. Children receiving medications or dialysis may also experience acute blood pressure fluctuations accompanied by debilitating symptoms. We aimed to describe the perspectives of children with CKD and their parental caregivers on blood pressure, to inform patient-centered care.

METHODS

Secondary thematic analysis was conducted on qualitative data from the Standardized Outcomes in Nephrology-Children and Adolescents initiative, encompassing 16 focus groups, an international Delphi survey, and two consensus workshops. We analyzed responses from children with CKD (aged 8-21 years) and caregivers (of children aged 0-21 years) pertaining to blood pressure.

RESULTS

Overall, 120 patients and 250 caregivers from 22 countries participated. We identified five themes: invisibility and normalization (reassured by apparent normotension, absence of symptoms, expected links with CKD); confused by ambiguity (hypertension indistinguishable from cardiovascular disease, questioning need for prophylactic intervention, frustrated by inconsistent messages, struggling with technical skills in measurement); enabling monitoring and maintaining health (gauging wellbeing, preventing vascular complications); debilitating and constraining daily living (provoking anxiety and agitation, helpless and powerless, limiting life activities); and burden of medications (overwhelmed by quantity of tablets, distress from unexpected side effects).

CONCLUSIONS

For children with CKD and their caregivers, blood pressure was an important heath indicator, but uncertainty around its implications and treatment hampered management. Providing educational resources to track blood pressure, and minimizing symptoms and treatment burden, may improve outcomes in children with CKD.

Combined therapy of hypertensive nephropathy with ginkgo leaf extract and dipyridamole injection and antihypertensive drugs: A systematic review and meta-analysis

BACKGROUND

In recent years, the incidence rate of hypertensive nephropathy has been increasing quickly, which has been a major threat to people's health. Renin-angiotensin-aldosterone system blockers have certain curative effects. However, there are some patients having serious adverse reactions, and the benefit population is limited, so the treatment of hypertensive renal damage is necessary to have beneficial supplement. More and more clinical studies have shown that ginkgo leaf extract and dipyridamole injection (GDI) combined with antihypertensive drugs has achieved good results in the treatment of hypertensive renal damage. It is supposed to be a supplementary treatment in hypertensive nephropathy.

OBJECTIVES

To systematically assess the efficacy and safety of GDI combined with antihypertensive drugs on hypertensive renal injury.

METHODS

Seven databases including PubMed, Cochrane Library, Embase, Wanfang database, China biomedical literature service system (Sino Med), VIP Chinese Sci-tech journal database (VIP), and China national knowledge internet (CNKI) were retrieved to collect randomized controlled trials (RCTs) in the experimental group containing combined therapy of hypertensive nephropathy with GDI and antihypertensive drugs. The retrieval time was from the establishment of database to July 8, 2020. Two researchers independently selected literature, extracted data, and evaluated the risk of bias in the study. The methodological quality was evaluated with Cochrane handbook and meta-analysis was performed with Stata 14.0 software.

RESULTS

Eight studies were included in this study which involved 556 patients. The meta-analyses indicated that, compared with using antihypertensive drugs alone, combined treatment of GDI with antihypertensive drugs can decrease 24-hour urinary total protein (weighted mean difference [WMD] -0.61, 95% confidence interval [CI]: -0.82, -0.39; k = 6, P ≤ .001), blood urea nitrogen (WMD -1.27, 95% CI: -2.45, -0.10; k = 6, P = .033, serum creatinine (WMD -29.50, 95% CI: -56.44, -2.56; number of estimates [k] = 6, P = .032).

CONCLUSIONS

Our meta-analyses showed that GDI combined with antihypertensive drugs can improve the renal function of hypertensive patients with renal injury.

Swimming Exercise Ameliorates Hypertension-Induced Kidney Dysfunction via Alleviating Renal Interstitial Fibrosis and Apoptosis

BACKGROUND

Hypertensive nephropathy is one of the major causes of ESRD. Exercise has been considered a nonpathological therapy for hypertension and its complications, yet mechanisms remain unclear. We sought to investigate whether periodic swimming could ameliorate hypertension-induced kidney dysfunction and its underlying mechanisms.

METHODS

Four-week male spontaneously hypertensive rats (SHRs) were randomly divided into the hypertension group (SHR, n = 8) and exercise group (SE, n = 8, 60 min swimming/day, 6 days per week, for 8 weeks). Wistar-Kyoto rats (WKY, n = 8) were served as a sedentary normotensive group. Bodyweight and blood pressure (BP) were recorded weekly. After 8-week sedentary or swimming exercise, lipids profile, BUN, and Cr were measured. The renal interstitial fibrosis was examined by the histopathological analysis using Masson's trichrome staining and hematoxylin and eosin staining. The kidney cell apoptosis was tested by TUNEL staining. The expressions of critical proteins responsible for the TGF-β1/Smad signaling of fibrosis, that is, TGF-β1, Smad2/3, and Smad7, as well as apoptosis related proteins, Bax and Bcl-2 in kidney cortex tissues were measured.

RESULTS

The 8-week swimming exercise reduced BP and bodyweight, lowered concentrations of BUN, and serum Cr, compared with SHR. Exercise remarkably inhibited hypertension-induced tubular degeneration, cellular cluster, and tubular cell swelling as well as glomerular degeneration in the kidney cortical tissues, attenuated renal interstitial fibrosis, and renal cell apoptosis. Moreover, expressions of TGF-β1, Smad2/3, and Bax were higher in the SHR than the WKY, which were significantly suppressed by the exercise. In contrast, hypertension-reduced expressions of Smad7 and Bcl-2 were enhanced by the swimming exercise. Strong correlations were found between kidney function indices, blood lipids, and key protein expressions.

CONCLUSION

Our results demonstrate beneficial effects of the periodic swimming on ameliorating hypertension-induced kidney dysfunction highlighting the potential of swimming exercise as a nonpathological therapy for early prevention of hypertension-caused kidney diseases.

Therapeutic potential of human induced pluripotent stem cells and renal progenitor cells in experimental chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a global public health problem. Cell therapy using pluripotent stem cells represents an attractive therapeutic approach for the treatment of CKD.

METHODS

We transplanted mitomycin C (MMC)-treated human induced pluripotent stem cells (hiPSCs) and renal progenitor cells (RPCs) into a CKD rat model system. The RPC and hiPSC cells were characterized by immunofluorescence and qRT-PCR. Untreated 5/6 nephrectomized rats were compared to CKD animals receiving the same amount of MMC-treated hiPSCs or RPCs. Renal function, histology, and immunohistochemistry were evaluated 45 days post-surgery.

RESULTS

We successfully generated hiPSCs from peripheral blood and differentiated them into RPCs expressing renal progenitor genes (PAX2, WT1, SIX2, and SALL1) and podocyte-related genes (SYNPO, NPHS1). RPCs also exhibited reduced OCT4 expression, confirming the loss of pluripotency. After cell transplantation into CKD rats, the body weight change was significantly increased in both hiPSC and RPC groups, in comparison with the control group. Creatinine clearance (CCr) was preserved only in the hiPSC group. Similarly, the number of macrophages in the kidneys of the hiPSC group reached a statistically significant reduction, when compared to control rats. Both treatments reduced positive staining for the marker α-smooth muscle actin. Histological features showed decreased tubulointerstitial damage (interstitial fibrosis and tubular atrophy) as well as a reduction in glomerulosclerosis in both iPSC and RPC groups.

CONCLUSIONS

In conclusion, we describe that both MMC-treated hiPSCs and RPCs exert beneficial effects in attenuating CKD progression. Both cell types were equally efficient to reduce histological damage and weight loss caused by CKD. hiPSCs seem to be more efficient than RPCs, possibly due to a paracrine effect triggered by hiPSCs. These results demonstrate that the use of MMC-treated hiPSCs and RPCs improves clinical and histological CKD parameters, avoided tumor formation, and therefore may be a promising cell therapy strategy for CKD.

Identification of hypertension in hospitalized children prescribed as-needed antihypertensive medication

Imperfect measurement conditions, transient blood pressure (BP) elevation due to pain or anxiety, and heavy clinical demands complicate hypertension (HTN) diagnosis in hospitalized children, and may prevent recognition of hypertensive episodes for children prescribed as-needed (PRN) antihypertensive medication. The authors sought to describe the incidence and predictors of missed BP elevation among hospitalized children prescribed PRN antihypertensive medication at our hospital. BP data were retrospectively audited for children age 2-18 admitted in 2018 to the general ward, and prescribed PRN oral nifedipine, intravenous [IV] or oral hydralazine, or IV labetalol. Appropriate recognition of BP elevation (exceeding the parameters in the medication order) was defined as administering medication within the ordered dosing interval, administering the medication earlier than planned, or physician documentation of why HTN treatment was withheld. Mixed-effects logistic regression was used to identify factors associated with recognition of BP elevation. Fifty-six hospitalizations including 616 BP measurements were analyzed. BP elevation was appropriately recognized in 230 (37%) instances, in most of which (n = 190) the antihypertensive medication was given after excessive BP was noted. On multivariable analysis, higher systolic BP and BP elevation occurring at night were associated with increased likelihood of appropriate recognition. BP elevations are frequently missed in hospitalized children prescribed PRN antihypertensive medication. Particularly, there was low recognition of diastolic BP elevation and of systolic BP elevation close to but still exceeding the ordered threshold. Further staff education may be needed to raise awareness of lower BP thresholds for HTN in younger and smaller children.

Ambulatory Blood Pressure Monitoring in Pediatrics

PURPOSE OF REVIEW

This is a review of ambulatory blood pressure monitoring (ABPM) use in pediatrics, summarizing current knowledge and uses of ABPM.

RECENT FINDINGS

Updated guidelines from the American Academy of Pediatrics have emphasized the value of ABPM. ABPM is necessary to diagnose white coat hypertension, masked hypertension, and nocturnal hypertension associated with specific conditions. There is growing evidence that ABPM may be useful in these populations. ABPM has been demonstrated to be more predictive of end-organ damage in pediatric hypertension compared to office blood pressure. ABPM is an important tool in the diagnosis and management of pediatric hypertension. Routine use of ABPM could potentially prevent early cardiovascular morbidity and mortality in a wide variety of populations.

Effect of (-)-epicatechin on the modulation of progression markers of chronic renal damage in a 5/6 nephrectomy experimental model

Aims

To evaluate the effects of (-)-epicatechin (Epi) in the progression of kidney damage.

Material and methods

We assessed the effects of Epi [0.01-20 mg/kg of body weight/day] during 14 days, in a 5/6 nephrectomy model in mice.

Key findings

Nephrectomy-induced systolic arterial hypertension was significantly reduced in a dose dependent manner with Epi treatment. Increased serum creatinine and urea were reduced almost to normal values. The concentration of tetrahydrobiopterin (BH4), used as subrogate of endothelial dysfunction, decreased in nephrectomyzed animals, Epi treatment increased BH4 levels almost reaching normal values. The expression of angiotensin II receptor (AT₁-R) and NADPH oxidase-4 (NOX-4) and 3-nitrotyrosine levels increased with nephrectomy and were reduced with Epi treatment. Renal tissue morphology in the remaining tissue was conserved with Epi treatment in a dose dependent manner.

Significance

Chronic kidney disease (CKD) is an independent cardiovascular risk factor associated with a mortality rate 10 to 20 times higher than that of the general population. High blood pressure, endothelial dysfunction and oxidative stress are important factors determining kidney damage progression. Findings of this study indicate that Epi is able to counteract the deleterious effects of subtotal nephrectomy and the structural and functional changes in the remnant kidney tissue, decreasing the progression of CKD. These results warrant the possibility of implement clinical trials to limit the progression of CKD in humans.

Management of Hypertension in CAKUT: Protective Factor for CKD

Patients with congenital kidney and urinary tract abnormalities (CAKUT) will often develop end-stage renal disease at some point and the need for renal replacement therapy is associated with high rates of morbidity and mortality. Hence, efforts to slow the progression of the disease are essential. Hypertension has been proven to be an independent risk factor for faster decline of glomerular filtration rate in renal patients, but studies involving only children with CAKUT are scarce. We performed a literature review to explore the association of hypertension with faster chronic kidney disease progression in children with CAKUT and also treatment options in this condition. A recent study reported an annual decline in GFR of 1.8 ml/min/1.73 m² among hypertensive patients with non-glomerular CKD, compared with 0.8 ml/min/1.73 m² in normotensive children. A multicenter prospective cohort in Brazil showed that a 1-unit increase in systolic blood pressure Z-score was associated with a 1.5-fold higher risk of disease progression. Since renin-angiotensin-aldosterone system activation is the most important mechanism of hypertension in these children, the first-line therapy involves the use of inhibitors of this axis, including angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers type I, which also promote an anti-fibrotic effect. Recent studies have shown a good safety profile for use in patients with chronic kidney disease and also in those with solitary kidneys. Hypertension is an independent risk factor for kidney disease progression and should be promptly managed for renal protection, especially among patients with CAKUT, the primary cause of chronic kidney disease in the pediatric population.